Fabric drawoff from knitting machines



May 6, 1969 c ER ET AL 3,442,100

FABRIC DRAWOFF FROM KNITTING MACHINES Filed March 14, 1967 Sheet of s May 6, 1969 c. F. MANGER ET AL 1 3,442,100

FABRIC DRAWOFF FROM KNITTING MACHINES Filed March 14, 1967 Sheet 3 of 3 May 6, 1969 c. F. MANGER ET AL 3,442,100

FABRIC DRAWOFF FROM KNITTING MACHINES Filed March 14. 1967 3 Sheet of 5 United States Patent US. Cl. 66153 2 Claims ABSTRACT OF THE DISCLOSURE A fabric drawotf device for a circular knitting machine having cooperating take-down rollers one of which is yieldably urged towards the other by spring means which is provided with a cam controlled mechanism for varying the resilient pressure between the rollers at predetermined times during the operation of the knitting machine as dictated by a control drum.

This invention is concerned with drawing off fabric as it is knitted from the needles of a circular knitting machine. Such drawing off is necessary to ensure proper casting-01f of stitches: the amount of pull required varying according to the weight of the yarn and the tension of the knitting. A garment may therefore require a different pull during the knitting of different parts. For example a sock having a heavier yarn in the top than in the leg, or portions incorporating terry loops, will require a different pull during the knitting of the top or of the portion incorporating terry loops from that required during the knitting of the remainder.

According to this invention a fabric drawoff device for a circular knitting machine comprises rollers capable of engaging fabric knitted by the machine and driveable so as to draw the fabric away from the needles, one of the said rollers being biased towards the other, and means for varying the pressure between the rollers and thus the pull on the fabric and the amount of slip between the rollers and the fabric according to the nature of the fabric being knitted. With a device according to this invention, the pull on the fabric can be varied during knitting to suit different requirements automatically through programming means for example a control drum.

A device according to this invention is preferably applicable to new and existing machines, and adapted to cooperate with the moving parts of the machine in conjunction with which it is to be used, that is to say rotatable with the needle cylinder if the latter rotates, driveable in cynchronism therewith, and compact enough to fit over the fabric container.

This invention provides a device for drawing off fabric from a circular knitting machine comprising rotatable take down rollers mounted on a carrier with one roller movable towards and away from the other, said rollers being driveable to rotate in opposite senses to draw off the fabric by means actuated by relative rotation between the needle operating cams on the one hand and the cylinder and roller carrier on the other hand, and the movable roller being urged resiliently towards the other roller, and having means for varying in controlled manner the pressure applied to the movable roller so as to vary the drawotf pull applied to the fabric. The means for urging the movable roller towards the other roller is preferably a coil spring, the tension in which can be adjusted by rotating a shaft to which one end of the spring is attached and the pressure applied to the movable roller thus varied. The means for varying the tension in the coil spring may be a linkage between a ratchet wheel fast on the shaft to which the coil spring is attached and the carrier support, for the provision of racking impulses for winding up the coil spring from the constant relative motion between the roller carrier assembly and the carrier support under the control of the control drum. The preferred means for varying the tension in the coil spring is a gear wheel fast on the shaft to which the coil spring is attached, a quadrant gear in mesh with the said gear wheel, a catch lever biased to lock the said gear wheel against rotation, an extension of the quadrant gear engaging the catch lever on rotation of the quadrant gear to lock the gear wheel, a cam follower surface on the quadrant gear, a cam introducable into the path of the quadrant gear as it is rotated past the said cam, the said cam rotating the quadrant gear through its cam follower surface to turn the said gear wheel to increase the tension in the spring and to brush the .said catch lever aside while the tension is increased, and a swivel cam separately capable of releasing the said catch lever to release the said gear wheel and reduce the tension in the spring.

This invention is illustrated by way of example in the accompanying drawings of which:

FIGURE 1 is a top perspective view of a fabric drawoff device according to this invention and part of a circular knitting machine upon which it is mounted;

FIGURE 2 is an end elevation of the rollers shown in FIGURE 1;

FIGURE 3 is a side elevation in the direction of an arrow III in FIGURE 2 omitting certain parts for the sake of clarity;

FIGURE 4 is a section along a line IV-IV of FIG- URE 2; and

FIGURE 5 is an end elevation of the device from the opposite side from FIGURES 1 and 2.

With particular reference to FIGURE 1, the device comprises a roller assembly RA of take down rollers 6 and 12 mounted on a bracket 20 and associated carrier 13 (FIGURES 2 and 3), the roller 12 being movable towards and away from the roller 6. The take down rollers 6 and 12 are rotatable through a pawl 55 and ratchet wheel 56 as shown in FIGURE 5 on a roller bracket wall 20b, the pawl 55 being on a pawl lever 57 operated by a quadrant gear 58 carrying a shoe 59 cooperating With an annular cam 7 on a bearing housing 1 which is part of the knitting machine. The bracket 20 and carrier 13 are rotatable in synchronism with the needle cylinder (not shown) of the knitting machine and a fabric container 5. A clutch (not shown) is provided to render the fabric take down inoperative during reciprocation of the needle cylinder. The rotary movement of the pawl and ratchet Wheel is transmitted from a gear 8 fixed to the take down roller 6 through intermediate gears 9 and 10 to a gear 11 which is fixed to the take down roller 12 so that the roller 12 is rotated in the opposite sense from the roller 6.

The carrier 13 is pivoted about an axis PA (FIGURE 2) and urged into the position shown by a coil spring 14 mounted on a shaft 15 along the axis PA as best illustrated in FIGURES 3 and 4. The coil spring 14 has a straight centre portion 14a engaging in a slot 160 at an end of a sleeve 16 surrounding the right hand half of the shaft 15 as shown in FIGURE 4, a coil portion 14b around the shaft 15 and clear of the shaft to allow for contraction, a coil portion 140 similarly around the sleeve 16, a hook end 14d engaging an end flange 13a of the carrier 13, and a hook end 14e engaging an end flange 13b of the carrier 13. The carrier 13 has a hand grip through which it can be pivoted about the axis PA by manual pressure to the position shown in chain dotted lines in FIGURE 2. The intermediate gear 10 is on the axis PA and so remains in mesh with the intermediate gear 9 in all positions of the carrier 13 and transmits drive to the gear 11 and thus to the take down roller 12 even when the roller 12 is not in contact with the take down roller 6, for example when the carrier 13 is held in the position shown in chain dotted lines in FIGURE 2. The shaft 15 has a shoulder 15a abutting the end of the sleeve 16 and the slot 160 but a portion of shaft 15 extends through the sleeve 16 to a threaded end 15b carrying a nut 17. The sleeve 16 has a bearing (FIGURE 4) in the flange 13b and a hexagonal end 16b through which it can be rotated. The shaft 15 and the sleeve 16 can be locked together by tightening the nut 17 on the thread 15b.

The roller assembly is mounted in bearing holes in end plates 18 and 19 as shown in FIGURES 3 and 4 secured to the sides of the roller bracket 20 by a screw 21 in the case of the plate 18, the corresponding screw 60 for the plate 19 being seen in FIGURE 5. The intermediate gear 9 is freely mounted on the bracket wall 20a and the intermediate gear 10 on the shaft 15 with a spacer washer 22 between it and the plate 18. A pinion 23 is keyed to the shaft 15 and retained by a circlip 52. The pinion 23 meshes with a quadrant gear 24 freely mounted on a stub spindle 25 secured to the bracket 20. Quadrant gear 24 forms a linkage arrangement with an upstanding cam 34 which cooperates with gear 24 in a manner described hereinbelow. The quadrant gear 24 has an extension 24a and a cam follower pin 24b. A catch lever 26 is rotatably mounted on a stub spindle 27 secured to the bracket 20 and is urged clockwise as seen in FIGURE 1 by a torsion spring 28 (FIGURE 2). The catch lever 26 has a recess for engaging the extension 24a of the quadrant gear 24 and a stop pin 51 secured to the wall 20a as shown in FIGURE 2 and projecting end 26a for engag ing the swivel cam 43 (FIGURE 1). An adjustable stop plate 29 is also rotatably mounted on the stub spindle 27. The stop plate 29 carries an adjustment screw 30 which bears on an arm 20a of the roller bracket 20. The amount of extension of the screw 30 determines the orientation of the stop plate 29 and the position of its stop member 29a which determines the lowermost position of the extension 24a of the quadrant gear 24 when released by the catch lever 26.

A platform 31 is clamped under two of the screws which secure lugs 1a of the bearing housing 1 to support arms 2a of the base 2 of the knitting machine. A plate 33 is attached to the platform 31 by a shoulder screw 32. The upstanding cam 34, formed from a segment of an annulus so that its camming surface 34a is helical, is secured to the plate 33. The plate 33 can be swivelled about the shoulder screw 32 against a tension spring 35 connecting one end of the swivel plate 33 to the platform 31. The spring 35 urges the plate 33 towards a stop (not shown) on the bearing housing 1. A cable connector 36 is the means through which the plate 33 can be moved away from the bearing housing 1 against the action of the spring 35. A cable 39 attached to the connector 36 passes through a post 37 secured to the platform 31 and a cable cover 38 to a bell crank lever 49 having a cam follower 49a controlled by a cam such as 48 on a control drum 4 driven from a gear box 3 of the knitting machine.

The platform 31 also carries a bracket 40 secured by screws 41 supporting a shoulder screw and nut 42 on which is mounted a swivel cam 43 having an arm 43a. The swivel cam 43 is held in the position shown in FIG- URE 1 by a tension spring 47 connecting the swivel cam to the bracket 40. The swivel cam 43 can be rotated about the shoulder screw 42 by means of a cable 46 anchored to the arm 43a. The cable 46 has an adjuster and passes through a cover 44 to a bell crank lever having a cam follower 50a controlled by a cam such as 48 on the control drum 4.

Pressure between the take down rollers 6 and 12 which provides the tension for the knitting is established by slackening the nut 17 .(FIGURE 4) and rotating the sleeve 16 through its hexagon end 16b. Because the end portions 14d and Me of the spring 14 are anchored to the flanges 13a and 13b of the carrier 13-, the winding up of the spring 14 will cause the carrier 13 to pivot about the axis PA until the take down roller 12 contacts the roller 6. The winding up of the spring 14 will also apply pressure through the teeth of the pinion 23 and of the quadrant gear 24 to force the extension 24a into contact with either the recess on the catch lever 26 or the stop member 29a. The torque in the spring 14 may be adjusted as desired and set by locking the shaft 15 and the sleeve 16 by tightening the nut 17 Variation in the pressure between the take down rollers 6 and 12 can be obtained by altering the position of the quadrant gear 24. If the initial setting was with the projection 24a supported by the catch lever 26 as shown in FIGURE 2 then upon removal of the catch lever 26 the quadrant extension 24a will be released and allow the spring 14 to unwind until the extension 24a contacts the stop 29a. If the initial setting was made with the quadrant extension 24a in the unpropped low position against the stop 29a then by turning the quadrant in a clockwise direction in FIGURE 1 until it is supported by the catch lever 26 as in FIGURE 2 the torque of the spring 14 and thus the pressure between the take down rollers 6 and 12 will be increased.

In order to increase the pressure between the take down rollers 6 and 12 a cam such as 48 on the control drum 4 is displaced from under the follower 49a. This releases the tension in the cable 39 and allows the cam 34 to move under the action of the spring 35 inwards towards the stop on the bearing housing 1. This is timed so that the cam 34 will spring inwards just prior to the passage of the quadrant gear 24 as it revolves with the roller assembly RA. The cam follower 24b on the quad rant gear 24 projects sufficiently to engage and run up the cam 34 thus rotating the quadrant gear 24 and the mating pinion 23 to increase the torque of the spring 14 and thus the pressure between the take down rollers 6 and 12. The catch lever 26 is automatically operated as the extension 24a of the quadrant gear 24 brushes past it and holds the gear 23 at the new pressure. The cam 34 may be withdrawn by means of a cam such as 48 on the control drum 4.

In order to reduce the pressure between the take down rollers 6 and 12, a cam such as 48 on the drum 4 is moved under the follower 50a to operate the cable 46 and tilt the cam surface 43 to a position in which it is contacted by the projecting end 2611 of the catch lever 26. As the roller assembly RA rotates past the cam 43, the catch lever 26 is pivoted to release the quadrant gear 24 and allow the torsion spring 14 to unwind until the extension on 24a rests on the stop 29a.

By adjustment of the crew 30 in the stop plate 29 various positions of the stop 29a may be obtained and thus varying degrees of reduction in the pressure between the take down rollers 6 and 12. The initial adjustment of the torsion spring may of course be similarly varied.

What we claim is:

1. In a circular knitting machine having needle operating cams and a needle cylinder between which relative rotation takes place, a fabric drawoff device comprising a pair of rotatable take down rollers, a bracket fixed in relation to the needle cylinder on which bracket said rollers are mounted, means mounting one of said rollers so as to be movable towards and away from the other roller, means for driving the rollers in opposite senses to draw off knitted fabric, said driving means being actuated by relative rotation between the needle operating cams on the one hand and the needle cylinder and roller bracket on the other hand, means urging the movable roller resiliently towards the other roller, means for varying in a controlled manner the pressure applied to the movable roller urging it towards the other roller so as to vary the drawoff tension applied to the fabric, the means for urging the movable roller towards the other roller comprising a coil spring, a shaft on which said coil spring is mounted, means connecting one part of the spring to the shaft, a toothed wheel attached to said shaft, a support for the bracket, a linkage acting between said toothed wheel and said bracket support means providing racking impulses for varying the tension in the coil spring on the occurrence of relative motion between the roller bracket and the bracket support, and means for controlling actuation of the impulse providing means.

2. A device in accordance with claim 1 wherein the said linkage include a quadrant gear which meshes with said toothed wheel, a catch lever biased to lock the toothed wheel against rotation, said quadrant gear having an extension serving to engage the catch lever on rotation of the quadrant gear to cause it to lock the toothed wheel, a cam follower surface provided on the quadrant gear, the said linkage also including a cam which 6 cooperates with the cam follower surface for rocking the quadrant gear to turn the toothed wheel and increase tension in the spring, and a swivel cam cooperating with the catch lever for releasing the said catch lever from the toothed wheel to reduce tension in the spring.

References Cited UNITED STATES PATENTS 381,963 5/1888 Stewart 66152 XR 783,144 2/1905 Scott 66l52 850,855 4/1907 Steber 66-152 1,198,448 9/1916 Houseman 66153 2,710,530 6/1955 Burdett 66-153 FOREIGN PATENTS 659,510 5/1938 Germany.

WM. CARTER REYNOLDS, Primary Examiner. 

